Licorice root, a complex product of nature and the only botanical known to contain appreciable levels of glycyrrhizin, has been subjected to many different procedures in efforts to realize the maximum yield of useful products from the root. Glycyrrhizin, one of the principal active ingredients in licorice root, is present in root at concentrations ranging from 2 to 15 percent. Techniques for extraction of active components from the root generally include initial comminution of the root and extraction with hot water and steam. In the past, a variety of agents have been used in an attempt to increase the yield of glycyrrhizin obtained from fresh licorice root. Typical of such efforts are the procedures described in U.S. Pat. Nos. 762,032; 1,389,663; 1,849,569; and 2,058,019 and British Specification No. 988. For the most part, the enumerated references describe procedures which rely on the addition of alkali, acid or both and/or other chemical agents to hot water and/or steam to increase the yield of glycyrrhizin from fresh root. Copending U.S. Patent Application Ser. No. 764,896, filed Feb. 2, 1977, and assigned to the assignee of the present application, describes certain glycyrrhizin-free fractions of licorice root and a process for obtaining those fractions from "spent" licorice root.
The primary water soluble extract obtained from licorice root is a natural flavor which is widely used; it is a product containing glycyrrhizin and many other water soluble components. Customary practice involves further treatment of the primary extract to obtain more highly refined and purified products. Commercial root processors typically treat primary extract with acid causing precipitation to occur, and isolate the acid insoluble fraction which is known in the industry as crude glycyrrhizic acid.
Crude glycyrrhizic acid is customarily treated with ammonia to render it soluble, forming ammoniated glycyrrhizin, a product of intense sweetness which possesses the characteristic licorice flavor, albeit at reduced intensity. Monoammoniated glycyrrhizin, a more highly refined ammoniated glycyrrhizin, has found utility for its sweet flavor, and very recently the interest in the sweetening and flavoring properties of monoammoniated glycyrrhizin, and other products of licorice root origin, has heightened as widely used synthetic sweeteners are criticized and removed from the market place by government edict.
Those searching for an ideal low calorie sweetener are not necessarily faddists, but they cannot help but be influenced by the current enthusiasm shown for all "natural" products. Ammoniated glycyrrhizin is recognized as a natural product, and it is presently on the FDA list of natural flavoring agents generally recognized as safe. Food processors, however, have been somewhat reluctant to accord this product complete acceptance.
Among the factors which mitigate against widespread acceptance of ammoniated glycyrrhizin and monoammoniated glycyrrhizin as products suitable for universal adoption as flavoring and sweetening agents include the fact that ammoniated glycyrrhizin and to a lesser degree monoammoniated glycyrrhizin, possess characteristic licorice flavor and thus, need to be used in low concentrations where that flavor is undesirable. Furthermore, ammoniated glycyrrhizin has limited sweetness value in comparison with saccharin, a factor which would seemingly call for higher concentrations of the product than is required when saccharin is used as a sweetening agent. There also appears to be some apprehension in the food industry that the "natural" status which ammoniated glycyrrhizin and monoammoniated glycyrrhizin currently enjoy may be questioned ultimately in view of their ammonia content. Ammoniated glycyrrhizin has been criticized by some as imparting an "ammonia" taste to food products; it has also been found that when raw products containing ammoniated glycyrrhizin are baked, ammonia gas may be liberated, and this is not desired. In addition, monoammoniated glycyrrhizin has limited solubility in water, only 1 to 2%, by weight, being soluble in hot water. At concentrations beyond this, monoammoniated glycyrrhizin forms a gel in aqueous solutions.
Monoammoniated glycyrrhizin and ammoniated glycyrrhizin base products such as those described in U.S. Pat. No. 3,851,073 enjoy considerable commercial acceptance, a fact which indicates that licorice root must be given further careful consideration as a source for low calorie sweeteners and natural flavors, despite their enumerated shortcomings. Therefore, it is an object of this invention to overcome the shortcomings associated with ammoniated glycyrrhizin and monoammoniated glycyrrhizin by providing potassium-magnesium-calcium glycyrrhizin in a form analogous to that in which glycyrrhizin exists in licorice root prior to aqueous extraction.